The _resourcesById folder is created when a resource is downloaded that has the same short name as another resource or project.
Deleting the copy in the folder will resolve the problem, it would be interesting to know why Paratext created it - I would expect that NIV84 would just install over itself.
A _projectsById folder can also be created when two projects on the machine have the same short name - the second will need to be received by using send/receive.
We were trying to support duplicated short names without having to completely change the structure of the “My Paratext Projects” folder.
John+Wickberg